Barking drum



Feb. 13, 1962 Filed June 5, 1958 J. J. HJRTSTER BARKING DRUM www@ 3 Sheets-Sheet 1 Feb. 13, 1962 J. J. HJRTsTr-:R 3.020,943

BARKING DRUM 5 Sheets-Sheet 2 Filed June 5, 1958 By y Feb. 13, 1962 J. 1. HJRTSTER BARKING DRUM 3 Sheets-Sheet 5 Filed June 5, 1958 mju United States atent Or 3,020,943 BARKING DRUM lacob Johansson Hjrtster, Gjovikbanen, Norway, as-

signor to Fibre Making Processes, Inc., Chicago, Ill., a

corporation of Illinois Filed .lune 5, 1958, Ser. No. 740,053 Claims priority, application Norway .lune 18, 1957 6 Claims. (Cl. 1444-208) This invention relates to improvements in barking drums.

To remove the bark from pulpwood the pulpniaking industry is using large revolving drums. Bark-covered logs are fed into one end of the drum and discharged at the other end with the bark removed. The barking is principally a result of the friction between the logs caused by the rotation of the drum, for there is not much barking eitect between the logs and the drum in prior-art drums.

The barking effect is comparatively small per unit length of the drum; so the barking drums are made large and long, and their maintenance has been quite expensive. The turning over of the mass of logs causes vibrations and shocks that are transmitted to the machinery, the supporting frame, and their foundations. Moreover, the barking is more efficient when the drum rotates at a high speed, and at high speed the stresses become very large because of the weights involved and the motion of heavy objects.

A major part of the maintenance concerns the fastenings for the barking irons, which have been unable to endure the huge strains caused by the tumbling of the mass of logs. Consequently, it has not been possible to run the barking drums at the higher speeds which give the best barking effect. The problem has been particularly severe when barking heavy wood.

Because of these difficulties, the barking irons have heretofore been secured to a series of rather closely spaced rings of wide channel shape, in order to get support that enables running at low or medium speeds without excessive maintenance costs. But the maintenance problem has not been satisfactorily solved by this expedient, and another problem has been created by it.

This other problem is that the rather close spacing of the channeled rings lengthwise along the drum has drastically reduced the area of the openings between the barking drums through which the removed bark can fall out. For example, in an excellent drum embodying current practice, only ll7" (9 feet, 9 inches) of the length of the drum is open in a total length of 22 feet, 81/2 inches.

As a result of the relatively small areas that remain open after installation of the supporting rings, not all the removed bark is able to fall out through the openings, and substantial quantities of bark have often come out the end along with the wood. There the bark has defiled the paper made from the pulp.

Also, when the logs tumble inside such drums, the bark gets pounded into the ends of the logs, and this bark is practically impossible to remove even with waterjets. This has long been considered a disadvantage of `drumbarkers, particularly with large units used at high speeds, for the presence of bark lowers the quality of the pulp and of paper made therefrom.

An important object of this invention is to provide solid support for and a strong connection between the barking elements or irons, which are longitudinal bars, and their numerous supporting rings, so that the drum can safely and economically rotate at higher speeds, with the resultant increases in the barking effect.

Another important object is to provide the drum with lengthwise openings of large size between the longitudinal bars and the supporting rings.

3,020,943 Patented Feb. 13, 1962 These objects have been achieved by a novel structure wherein the barking irons are fastened rto the supporting rings so solidly that the drum can operate at higher speeds without causing increased maintenance costs. As a result, the barking effect is enhanced. Also, the connection between the irons and the rings is so solid that some of the wide channeled rings can be replaced by narrow rings, thereby increasing the size of the openings through which the bark can fall. The bark thus can fall through the openings instead of coming out the end of the drum with or knocked into the wood.

Another object is to obtain a free outlet for the bark and to provide a novel bar shape that keeps the bars clean of bark during the barking process.

Another object of the invention is to obtain a more eifective bark removal. This improvement is obtained from the action upon the logs of novel longitudinal V-shaped bars which are mounted on the inside of the barking drums separated from each other and serve as the barking elements.

Another object is to provide a structure that absorbs the shocks and vibrations produced by operation of the barking drum.

Some of these latter objects are achieved by providing a novel attachment of the barking elements to the drumstrengthening rings, by providing the elements themselves with a comparatively flat cross section at their radially inner extremity, usually called the top surface, and by providing that surface with ridges or grooves extending the length of the bar, the ridges being shallow in relation to the height of the bar itself. One or more of these ridges may, in accordance with this invention, be shaped like blunt knife edges set in the direction of the rotation of the drum. Or, also according to this invention, the top of one or more of these ridges may have grooves with identical edges on each side.

Other objects and advantages of the invention will appear from the following illustrative embodiments thereof.

In the drawings:

FIG. l is a view in end elevation of a barking drum assembly embodying the principles of the present invention.

FIG. 2 is a view in side elevation of the drum assembly of FIG. 1.

FIG. 3 is an enlarged view in side elevation of the drum proper of FIGS. l and 2 showing the attachment of the bars to a series of supporting rings.

FIG. 4 is a fragmentary View similar to FIG. 3 of a portion of a modiied form of drum also embodying this invention.

FIG. 5 is an enlarged fragmentary view in section along the line S--S in FIG. 3.

FIG. 6 is a further enlarged fragmentary view in section taken along the line 6--6 in FIGS. 3 and 7 and showing a preferred structure of barking element and the support therefor.

FIG. 7 is a fragmentary view looking at FIG. 6 along the arrow 7.

FIG. 8 is a view similar to FIG. 7 looking at another point along the drum showing the use of narrow rings which, according to this invention, can replace the wide channels at some points along the drum.

FIGS. 9, l0, ll, and l2 are enlarged cross-sectional views of four different shapes of modied forms of barking elements according to the invention.

FIGS. 13 and 14 are views in section taken respectively along the line 13-13 in FIG. 9 and lf3-14 in FIG. ll, showing how the barking elements are fastened to the supporting rings.

in FIGS. 3 and 16.

FIG. 16 is a view in section taken along the line 16--16 in FIG. 15.

In the barking rum assembly shown in FIGS. l and 2 a drum 1 is suspended by chains 2 which run over a drive sprocket Wheel 3 and idler sprocket wheel 4. To avoid vibration, the supporting frame may comprise individual sections 5 supported on a base 6. The lateral position of the drum 1 is maintained by rollers 7. The drum 1 may be driven from a motor 8 mounted on the frame 5, acting through gears 9 and 19.

The drum 1 comprises longitudinally extending barking irons 11 supported by a series of channel rings 12 and, according to this invention, also by some narrow rings 30, which replace some of the channel rings 12 normally used. Preferably, the barking irons 11 cornprise M-bars, as shown in FIGS. 1 8, with apexes 13 and 14 of the M facing radially inwardly and with V-shaped recesses 15 and 16 on their radially outer surfaces 17. The two recesses and the apexes are separated by a flat central portion 18.

FIGS. 6 and 7 show how this invention secures a longitudinal M-bar 11 to a channel ring 12. In part this is achieved by securing the barking iron 11 directly to the channel rings 12 by longitudinal welds 19 as is current practice. But more important is Vthe reinforcement of this by securing each M-bar to a plate having a pair of V-shaped projections'Zl and 22 that match and fit into the V-shaped recesses 15 and 16 and abut the' outer surface 17, except for cut off ends 23 that assure contact along the edges. Welds 24 along the abutting portions secure the plate 20 to the bar 11, and then edges 2S are secured to side flanges 26 and 27 of the channeled rings 12 by welds 2S.

FIG. 8 shows a narrow ring 3G instead of a channel ring 12. The ring is fastened to the N'bar 11 by plate elements 20 welded to the sides of the plate ring 30hy welds 31 and also to the inside hollows 15 and 16 of the M-bar 11 by the welds 24.

Use of the several rings 30 in` place of some of the conventionally used channel rings 12 is shown in FIGS. 3 and 4. In FIG. 3 the area of the openings 35 through which the bark can fall out has been increased byabout 31% over the prior-art structure solely by replacement of four of the channel rings 12 with narrow rings 30. In the FIG. 4 structure the openings 35 have been increased in area by about 31% by using these narrow rings 30.

In addition, the strength of the drum 1 and the solidity of the support for the irons 11. is greatly increased by use of the plates 20 and by welding them to the inside hollows 15 and 16 of the M-bar 11 as well as to the rings 12 or 30.

In an alternative from of barking element 40, shownV in FIG. 9, the top surface 41 which comes in contact with the logs is provided with a number ofl comparatively small ridges 42. When the drum 1 rotates, the ridges 42 serve to rub bark off the logs. For promoting the agitation of the log pile, the bars 49 are shaped with round shoulders 43.

In the modified form of barking element 45 shown in FIG. 10, ridges 46 are shaped as sharp teeth 47 directed with the rotation of the drum 1.

In the modification shown in FIG. 11 a bar 50 isprovided with one or more somewhat larger ridges 51. Between these ridges 51 on the top is a groove 52 such that identical ridges 51 are on oppositev sides of the groove 52.

FIG. 12 shows a V-shaped barking element 55 provided on top with ridges 56 and groove 57.

Referring to FIG. 13, the longitudinal barking irons 40 are fastened to channel rings 12in a manner basically similar to the structure shown in FIGS. 6-8. One side 60 of the bars 40 is welded at 61 to one side 62 of the ring 12 across the whole width. The rings `12.-areV U-shaped and comparatively wide and are used in suf cient number to make drum 1 rigid. The all-important reinforcing of the connection between the bars l0 and the rings 12 is the plate element 63 (basically like the plate element 23) arranged on one or both sides of the rings 12 and filling out the inside hollow 64 of the barking element 49. Moreover, the plate 63 is welded both to the inside hollow 64 of the bar 40 and to the side 65 of the ring 12. Welds 66 and 67 are shown. Longitudinal openings 68 between the bars 40 and rings 12 provide for the disposal of the removed bark.

FIG. 14 shows section of another ring 3U which gives a solid support for bars 50 at points between the broad rings 12. The plate rings 3i) take little room and so help to provide large openings 35 shown in FIG. 3 that serve as bark outlets. The ring 30 is well adapted for fastening to the bars by plate elements 70 basically like the plate elements 26. The joint is very solid because the plate element 7i) is welded at 71 in the hollow 72 of the bar 50 and to the side of the plate ring 30. The broad rings 12 can therefore be reduced in number. The rings 30 are also well adapted for bolting a sprocket ring or guide ring 73f for the rotation of the drum. A barking drum 1 employing these comparatively narrow bars Si) fastened to plate rings 70 has much larger area of openings for bark outlet than previous known types.

In order to further increase the barking effect, the barking irons o'r the ridges on them may also have grooves, waves, corrugations, or other uneven surfaces, as seen in longitudinal section. To avoid brooming of the logs, all surfaces of the barking elements may be rounded.

The barking irons may, of course, have other shapes lying within the scope of this invention. Thus, the irons may have larger or smaller ridges or grooves and be of oval, prismatic, or other suitable cross section. Also, the drum may also be suspended eccentrically such that the center of gravity is off center. In this case the drum would be supported by guide wheels 7 on only one side.

The capacity of the drum 1 may be increased by dividing the drum into several comparatively short sections which can be rotated at different speeds.

FIGS. l5 and 16 show the application of the invention to a drum having a'removable end piece. The M- bars are secured to plate elements 29 as before. The plate elements 20 are secured to a large fixed end ring by welds 81, and the fixed end ring 80 is secured to a removable end ring by countersunk rivets 83. When the end ring 32 becomes worn by the logs, it can be removed by knocking out the rivets 83 and putting in a new ring S2.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

l. In a rotary barking drum providing a log receiving chamber and comprising a plurality of circular rings the side walls of which are disposed in a longitudinal spaced arrangement about the axis of said drum, and an annular series of elongated circumferentially spaced barking irons extending normal to the sides of said rings and adjacent the inner periphery thereof within said chamber, the irnprovement comprising each of said barking irons having cooperating walls converging inwardly of said chamber from said rings and providing therebetween outwardly facing recesses on one side of said cooperating walls and a barking surface on the opposite side thereof facing said chamber, relatively flat plates having portions connecting and reinforcing said irons from said rings, one of said portions having an elongated outer edge and side lying ush against a side wall ofen-associated-ring-and-tbeing` welded thereto, and another of said portions having converging inner edges extending into said recesses in said irons and being welded to the corresponding converging walls thereof, whereby to provide a circumferentially reenforced functionally integral drum structure for the purpose intended.

2. The drum of claim 1 in which some of said rings are wide channel-shaped members with radially outwardly extending ilanges while other of said rings are of simple bar construction, said other rings being much narrower than said channel-shaped members and being spaced between successive said channel-shaped members for imparting additional strength to said drum without consuming excessive space.

3. The structure recited in claim l in which said barking surface on the opposite side of said irons and facing said chamber is formed with longitudinally extending ridges thereon.

4. The structure as recited in claim 1 in which edges of said cooperating converging walls of said irons are welded to inner peripheral portions of said rings.

5. The structure as recited in claim 4, and in which said barking surface comprises circumferential spaced barking ridges.

6. A barking drum comprising: a plurality of circular supporting rings spaced longitudinally from each other and having side walls each lying in radial planes; a plurality of longitudinally extending barking irons spaced circumferentially from each other and lying radially inside said rings, each iron being substantially M-shaped in cross section with the apexes of the Ms facing radially inwardly and the legs facing radially outwardly, to provide a pair of V-shaped recesses between converging walls on the outer surface of said irons, the bases of the legs being secured to said rings by longitudinally extending welds; and reinforcing and securing plates each having a pair of generally V-shaped projections extending into said V-shaped recesses, inner portions of side edges of said projections being welded to both of said converging walls of said outer surfaces, each plate having an outwardly extending portion with a side surface abutting a side wall of said ring and with the outer portions of said side edges and an outer edge joining said side edges all being welded to said side wall.

References Cited in the file of this patent UNITED STATES PATENTS 1,844,498 Candy Feb. 8, 1932 2,592,054 Mertz et a1. Apr. 8, 1952 2,688,350 Waller Sept. 7, 1954 2,897,858 Hanson Aug. 4, 1959 FOREIGN PATENTS 50,571 Norway Apr. 11, 1932 54,315 Norway Aug. 27, 1934 86,408 Sweden May 26, 1936 63,370 Norway May 24, 1941 

